The governor said the health risks of trying to change a child’s sexual orientation, as identified by the American Psychological Association, trump concerns over the government setting limits on parental choice. ‘‘Government should tread carefully into this area,’’ he said in the signing note, ‘‘and I do so here reluctantly.’’

California has also banned the practice, which is known as conversion therapy.

The decision marked the third time this month that Christie has staked out a moderate position on a hot-button social issue as he seeks a second term in a Democratic-leaning state. It also offers more evidence that the popular governor is positioning himself as a pragmatist who shuns more conservative elements within his party.

Christie found middle ground on medical marijuana for children when he agreed Friday to allow growers to cultivate additional strains and for marijuana to be made in an edible form for chronically ill children. But he would not lift a provision that could require as many as three doctors to sign off on a prescription.

Last week, Christie vetoed a ban on .50-caliber rifles that was opposed by firearms rights advocates and gutted a proposed overhaul of the state’s gun permit law that relied on undeveloped technology.

Recently, he signed 10 less-significant gun measures the Democrat-led Legislature passed after last year’s deadly school shooting rampage in Newtown, Conn.

Republican leader in democratic state

The decisions allow Christie to quiet some of the criticism he could face from conservatives by offering specific reasons why he was taking the steps, often citing compassion for the needs of children and families.

In signing the ban, Christie reiterated his belief that people are born gay and homosexuality is not a sin, a position he first stated in a 2011 interview with CNN. That view is inconsistent with his Catholic faith, which teaches that homosexual acts are sins.

Christie said on ‘‘issues of medical treatment for children we must look to experts in the field to determine the relative risks and rewards,’’ citing a litany of potential ill effects of trying to change sexual orientation, including depression, drug abuse, and suicide.

‘‘I believe that exposing children to these health risks without clear evidence of benefits that outweigh these serious risks is not appropriate,’’ he said.

Christie, however, has not moderated his position on gay marriage, which he vetoed and continues to oppose. As a result, gay rights activists applauded Monday’s bill signing but pushed for more.

‘‘It is our truest hope that the governor will realize, as the majority of the legislature and a super-majority of the public have realized, that the best way to ensure lesbian, gay, bisexual, transgender youth are protected from the abuse of being ostracized is to provide them with equality,’’ Troy Stevenson, executive director of the state’s largest gay rights group, Garden State Equality, said in a statement.

Christie has said he supports the state’s civil union law, which was enacted to give gay couples the benefits of marriage but not the title. Several couples have since sued, saying the law provides them unequal treatment. A court decision is expected next month.